In the packaging industry, the need to produce increasingly larger boxes quickly and economically demands the advent of an improved machine capable of simultaneously forming two seams in a two-piece oversized box. Today""s commercially-available equipment is capable of stapling or gluing only one seam at a time. Because of the demand for larger sizes, most boxes generally require the use of separate box pieces and the formation of two seams. Forming an additional seam creates material handling problems and inefficient double feed requirements. Moreover, as the stapling process is becoming a less desirable method of seam fastening, many manufacturers rely on a hot glue method which is relatively expensive, and requires close attention to machine maintenance for continued operation. Cold glue methods appear to be a desirable alternative. The prolonged cure time, however, adds to the difficulties in material handling thus making this choice unattractive to most manufacturers.
In addition to the seam forming issues discussed above, larger boxes made with relatively heavy pieces are physically difficult to handle and feed into the seaming machine. The typical outside dimension of a large box piece may be 180xe2x80x3xc3x97any length, limited only by the material handling capabilities of the manufacturer. Prior to feeding, the heavy box pieces must be properly aligned. It is critical that the edges to be glued are matched up square and true, and remain in that condition throughout the seaming process. Processing speeds must also remain consistent between various handling components in order to prevent miss-feeds.
Therefore, it is an object of the invention to provide a box seaming machine which operates to form both seams of a two-piece box in a single pass.
It is another object of the invention to provide a box seaming machine which reduces the incidence of damage, skewing and miss-feeds.
It is another object of the invention to provide a box seaming machine which has an increased production rate.
It is another object of the invention to provide a box seaming machine which is capable of producing as many as one box every 20 seconds.
It is another object of the invention to provide a box seaming machine which utilizes either a cold set or hot melt glue, staples, or tape to secure the seams of the box.
It is another object of the invention to provide a box seaming machine which does not cause unwanted permanent creasing of the corrugated box panels.
It is another object of the invention to provide a box seaming machine which promotes an accelerated xe2x80x9ccurexe2x80x9d cycle compatible with the operating speed of the machine, thereby allowing use of a more cost-effective adhesive.
It is another object of the invention to provide a box seaming machine which simultaneously forms two seams joining the box pieces without the need for double handling.
It is another object of the invention to provide a box seaming machine which can be readily modified to utilize hot glue or staples as a fastening method without major changes to the machine.
It is another object of the invention to provide a box seaming machine which uses two glue heads capable of running independently to simultaneously produce two smaller boxes each with a single seam.
It is another object of the invention to provide a box seaming machine which is capable of seaming a square box.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a box seaming machine for assembling an oversized box including first and second box pieces. Each of the box pieces is folded to form top and bottom panels having respective proximal edges joined together at the fold and respective free edges opposite the joined edges. The free edges of the first box piece are adapted for being secured to the free edges of the second box piece to define first and second seams of the assembled box. The box seaming machine includes a pair of laterally-spaced, opposing drive roller assemblies adapted for movement between an idle position and an operative position. In the idle position, the drive roller assemblies are disengaged from the box pieces to enable alignment of the free edges prior to seaming. In the operative position, the drive roller assemblies frictionally engage the box pieces at respective folds and feed the box pieces downstream for seaming. First and second seam fasteners are located downstream of the drive roller assemblies for securing the seams at respective free edges of the first and second box pieces to form an assembled, two-piece box.
According to another preferred embodiment of the invention, the drive roller assemblies are carried on a common drive shaft such that the box pieces are fed into the machine at corresponding rates.
According to another preferred embodiment of the invention, the drive roller assemblies include respective upper and lower rollers.
According to another preferred embodiment of the invention, the drive roller assemblies include respective lift carriages. Each of the lift carriages is mounted adjacent the lower roller such that when the drive roller assembly is in the idle position, the lift carriage supports the box piece above the lower roller. When the drive roller assembly is in the operative position, the lift carriage moves away from the box piece to position the box piece on the lower roller.
According to another preferred embodiment of the invention, the upper rollers are mounted to respective lift carriages, and move in unison with the carriages upon movement of the drive roller assemblies between the idle and operative positions.
According to another preferred embodiment of the invention, respective cylinders are provided for moving the drive roller assemblies between the idle and operative positions.
According to another preferred embodiment of the invention, a guide roller is located between the drive roller assemblies for supporting and guiding one or more of the box panels as the box pieces move downstream into the machine.
According to another preferred embodiment of the invention, the seam fasteners include respective upper and lower glue shoe assemblies adapted for simultaneously applying glue to respective free edges of the box pieces to secure the seams of the assembled box.
According to another preferred embodiment of the invention, the upper glue shoe assembly defines a cavity for storing a cold glue head.
According to another preferred embodiment of the invention, the upper glue shoe assembly includes an edge guide surface for guiding one of the first and second box pieces into the machine during seaming.
According to another preferred embodiment of the invention, the lower glue shoe assembly defines a cavity for storing a cold glue head.
According to another preferred embodiment of the invention, the lower glue shoe assembly includes an edge guide surface for guiding one of the first and second box pieces into the machine during seaming.
According to another preferred embodiment of the invention, the lower glue shoe assembly further includes a flat support surface extending perpendicular to the edge guide surface, and cooperating with the edge guide surface to square and align one of the first and second box pieces prior to seaming.
According to another preferred embodiment of the invention, the lower glue shoe assembly further includes a stop formed at a back end of the support surface, and extending perpendicular to the support surface to further square and align one of the first and second box pieces prior to seaming.
According to another preferred embodiment of the invention, a cylinder is provided for lowering the support surface of the lower glue shoe assembly to disengage the box piece from the stop prior to downstream movement of the box piece into the machine.
According to another preferred embodiment of the invention, first and second laterally-spaced compression arms are located downstream of the upper and lower glue shoe assemblies, and arranged to receive the assembled box pieces at the glued seams to compress the seams in a curing zone as the box pieces move downstream through the machine.
According to another preferred embodiment of the invention, first and second pairs of upper and lower nip rollers are located at respective leading ends of the compression arms, and cooperate to pull the box pieces from the glue shoe assemblies into the curing zone.
According to another preferred embodiment of the invention, the first and second compression arms extend downstream at an incline such that the box pieces are fed into the machine at a relatively low elevation, and are discharged from the machine at a higher elevation.
According to another preferred embodiment of the invention, a box elevator is located at an output end of the machine for receiving assembled boxes after seaming, and lowering the boxes to an elevation for unloading.
In another embodiment, the invention is a method of assembling an oversized box including first and second box pieces. Each of the box pieces is folded to form top and bottom panels having respective proximal edges joined together at the fold and respective free edges opposite the joined edges. The method includes the steps of aligning the box pieces at an in-feed section of a box seaming machine such that the free edges of the top panels of the box pieces overlap to form a first seam, and the free edges of the bottom panels of the box pieces overlap to form a second seam. The box pieces are then clamped at respective folds between upper and lower rollers of respective first and second drive roller assemblies. The drive roller assemblies are then actuated in unison to move the box pieces downstream at corresponding feed rates. As the box pieces move downstream, the first and second seams are fastened to form an assembled, oversized box.